I use both, but seem to gravitate towards the soaps first. They seem to be a more 'authentic element' of straight shaving. Brush, mug, soap and razor provide me with a complete feeling of satisfaction. That said, I think that some of the creams can provide a superior shave, too, (LOVE the Cremo Creme from Ray's - use it as a pre-shave, too!) and I like the Taylors right now; will be getting some Vulfix, and some Trumpers soon to try as well!
I see the soaps and creams as a fun variable, moreso than the razors, and a fun, cheap way to add to the repertoir!
Best,